diff --git a/spot/twaalgos/gfguarantee.cc b/spot/twaalgos/gfguarantee.cc
index 9b43c6a0e..c4296d41f 100644
--- a/spot/twaalgos/gfguarantee.cc
+++ b/spot/twaalgos/gfguarantee.cc
@@ -99,7 +99,9 @@ namespace spot
           for (auto& e: aut->out(init))
             aut->new_edge(accstate, e.dst, e.cond, {0});
           // This is not mandatory, but starting on the accepting
-          // state helps getting shorter accepting words.
+          // state helps getting shorter accepting words and may
+          // reader the original initial state unreachable, saving one
+          // state.
           aut->set_init_state(accstate);
         }
 
@@ -137,7 +139,7 @@ namespace spot
     twa_graph_ptr reduced = minimize_obligation(aut, f, nullptr,
                                                 !deterministic);
     scc_info si(reduced);
-    if (!is_terminal_automaton(aut, &si, true))
+    if (!is_terminal_automaton(reduced, &si, true))
       return nullptr;
     do_g_f_terminal_inplace(si, state_based);
     return reduced;
@@ -148,7 +150,7 @@ namespace spot
                      bool deterministic, bool state_based)
   {
     twa_graph_ptr res = gf_guarantee_to_ba_maybe(gf, dict,
-                                              deterministic, state_based);
+                                                 deterministic, state_based);
     if (!res)
       throw std::runtime_error
         ("gf_guarantee_to_ba(): expects a formula of the form GF(guarantee)");
diff --git a/tests/core/ltl2tgba.test b/tests/core/ltl2tgba.test
index 81699d253..b1ede0f1b 100755
--- a/tests/core/ltl2tgba.test
+++ b/tests/core/ltl2tgba.test
@@ -1,6 +1,6 @@
 #!/bin/sh
 # -*- coding: utf-8 -*-
-# Copyright (C) 2009-2017 Laboratoire de Recherche et Développement de
+# Copyright (C) 2009-2018 Laboratoire de Recherche et Développement de
 # l'Epita (LRDE).
 # Copyright (C) 2003-2004 Laboratoire d'Informatique de Paris 6
 # (LIP6), département Systèmes Répartis Coopératifs (SRC), Université
@@ -278,3 +278,6 @@ test 4 = `ltl2tgba -f "$f" --low -x tls-impl=0 --stats=%s`
 test 3 = `ltl2tgba -f "$f" --low -x tls-impl=1 --stats=%s`
 test 2 = `ltl2tgba -f "$f" --low -x tls-impl=2 --stats=%s`
 test 2 = `ltl2tgba -f "$f" --low -x tls-impl=3 --stats=%s`
+
+# This is not optimal, the smallest DBA for this formula has 2 states.
+test 3 = `ltl2tgba -BD -f 'GF((p0 & GF!p0) | (!p0 & FGp0))' --stats=%s`